1. Field of the Invention
Factor VIIIC is a plasma protein that participates in the intrinsic pathway of blood coagulation. It is absent or defective in individuals with the hereditary X chromosome-linked recessive bleeding disorder hemophilia A. Great difficulty has been encountered in isolating Factor VIIIC due to its extremely low concentration in plasma and the fact that it appears to be an intermediate or final degradation product of a larger protein precursor. Efforts to isolate Factor VIIIC have led to complex mixtures of various polypeptides having significant heterogeneity and varying molecular weights.
It would be of great interest therefore to prepare monoclonal antibodies which are capable of selectively reacting with individual polypeptides or groups of polypeptides which are derived from Factor VIIIC.
2. Description of the Prior Art
U.S. Pat. No. 4,361,509 and references cited therein describe purification of Factor VIIIC. See also Fulcher and Zimmerman, Proc. Natl. Acad. Sci. USA (1982) 79:1648-1652. Tuddenham et al., J. of Lab. Clinical Medicine (1979) 93:40-53 describes purification of Factor VIIIC using polyclonal antibodies. Austen, British J. Hematology (1979) 43:669-674 describes the use of aminohexyl-Sepharose for Factor VIIIC purification. Weinstein et al., Proc. Natl. Acad. Sci. USA (1981) 78:5137-5141 describes a study of the effect of thrombin on Factor VIIIC. See also Kuo et al., Abstracts for IX International Congress of Thrombosis and Hemostasis, (Stockholm; July, 1983).
Hybritech Data Sheet (Hybritech, Inc., 11085 Torreyana Road, San Diego, Calif. 92121) describes a monoclonal antibody (Catalog #0432) which is specific for human Factor VIIIC. Danish patent application No. 53519 corresponding to U.S. patent applications Ser. Nos. 481,103 filing date 3-31-83 and 556,508 filing date 11-30-83 describes the preparation of monoclonal antibodies to human factor VIIIC and polypeptide fragments thereof. Certain of the monoclonal antibodies described in the Danish patent application are also described by Zimmerman et al. (1983) Blood 61:807. Fass et al. (1982) Blood 59:594, report that active human Factor VIIIC may be eluted from monoclonal antibodies by ethylene glycol (50%).